home audio gurus...

[SteveB]

I've owned a pair of Infinity Kappa 8.1's for years that I picked up at a garage sale ($75 bucks for the pair plus an M&K power sub, hah!), but I've never had an amplifier that can power them properly. I've been using an old Sony receiver that just isn't that great and is incapable of providing tight bass with these speakers.

According to scuttlebutt the Kappa's seem to need an amp that can provide a high current. They definitely are not particularly efficient. I don't want to spend a buttload of money on extreme audiophile, but I need to provide sufficient power to these bad boys. I could go with a receiver, or a pure poweramp, either a stereo version or even a couple of monoblocks. Might even be tempted to bi-amp if it makes sense. Any suggestions if I want to keep the price south of $1000? I've thought about pressing a QSC PA amp into service, but my guess is thats not particularly designed for hi fidelity audio. If I go the poweramp route, then I'd have to look for a control preamp of some sort I suppose as well.

[JohnnyB]

I recommend you take receivers out of the conversation. Although there have been a few through the years that are capable of high current (e.g., McIntosh, Tandberg), in general when a hi-fi maker crams a tuner, a preamp, and an amp onto a chassis, they save space by cutting down the power supply, and that shrinks the amp's ability to deliver current.

To get new gear at about $1k or less that powers these speakers properly, here are some possibilities. Note that some of these offerings are sale-priced which

Emotiva:

Preamp ($404)

125 wpc stereo power amp ... or

two 250wpc mono power amps (still comes in at about $1k total)

Outlaw Audio:

Two of these 200-watt mono power amps at $598 the pair.

Anthem Audio (a division of Paradigm Speakers):

The Anthem 225 Integrated amp. This one has high power (225 wpc into 8 ohms), high current (330 watts into 4 ohms), and includes built-in phono and line level preamp. The downside is that this unit is about $1500 but the word is that it's about the best thing under $2K out there. High power and good sound for a reasonable price.

NAD:

80wpc integrated amp, $799

150wpc integrated amp, $1299

You might also want to look into some separates offered by overachiever Parasound. In particular check out the Classic series of amps and the preamp.

[SteveB]

cool, thanks for the suggestions. What is the general feeling on Marantz stuff as well? Their HDMI capable preamp looks interesting, at some point I'm going to have to have something with HDMI switching. Also, if you go the separates route, I assume an EQ unit is needed for tone shaping?

[ArnieZ]

I have a Creek EVO integrated amp that has a solid 85w/channel into 8 ohms. I believe the price is around 1k. the current output is listed @ > than 10 amps RMS into 1 ohm. I don't know if this is high current or not! It does use a torroidal transformer which I believe have higher current for their size. It is a really nice sounding amp,very musical.

ArnieZ

[JohnnyB]

...What is the general feeling on Marantz stuff as well?

Marantz stuff in general is well designed and made, and performs well. This power amp should be a good power and current match for your speakers, and the price is OK if you find a good simple line stage preamp. That one by Emotiva, for example.

Their HDMI capable preamp looks interesting, at some point I'm going to have to have something with HDMI switching.

OK. This complicates things a bit and may change budgetary considerations. What are your long-range plans? Do you already have an HDTV? How many HDMI inputs does it have? If you're planning to get an HDTV, most of them now can switch among 4 HDMI inputs.

The Marantz AV7005 A/V preamp can even do HDMI 1.4 (3D) switching (one of the few that do), but it's $1499. It's an excellent unit. Are you willing to stretch the budget a bit?

Maybe you should consider the Parasound Classic 2100 stereo preamp. It functions as a 2-channel stereo preamp, but also has a home theater bypass, enabling you to integrate it with a surround sound processor so you can switch between surround home theater and 2-channel audio. It also has a subwoofer output with separate volume control. With this unit, you could base your current stereo on a high quality 2-channel preamp, and still use it if you later move to a home theater surround unit.

You can also buy outboard HDMI switchers that range from about $30 to $300.

Also, if you go the separates route, I assume an EQ unit is needed for tone shaping?

I don't understand the basis of that assumption. Is it because separates often don't have tone controls? An analog outboard EQ unit introduces a fair amount of tone suckage and throws off the phase relationships. For 2-channel I prefer room matching via speaker placement and room treatment.

AV pre/pro's that have tone shaping in the digital domain (such as Audyssey) to dial in a surround system to the a/v room are another matter. They can match the eq to the room response in the digital domain without affecting transparency or phase relationships.

[JohnnyB]

I have a Creek EVO integrated amp that has a solid 85w/channel into 8 ohms. I believe the price is around 1k. the current output is listed @ > than 10 amps RMS into 1 ohm. I don't know if this is high current or not! It does use a torroidal transformer which I believe have higher current for their size. It is a really nice sounding amp,very musical.

ArnieZ

I've always liked Creek. Their integrated amps manage to have much of the magic of a much more expensive stack of separates. I didn't mention the Evolution 2 for the Infinity Kappas: they would have sounded marvelous in the midrange and treble, but I don't think they'd bring out the best in the low end. Creek's 140 wpc rating into 4 ohms is impressive, but 10 amp peak current isn't all that. The amp I'm currently listening through puts out 45 amps, and I have another that can hit brief peaks of 80.

Of the amps I listed previously, I'd rank the Anthem 225 as the best one-box solution. For a 4-way floorstanding speaker (especially with a 12" woofer) begs for something to push through that much network filtering. I'd recommend 150 wpc, high current, and high damping factor. At 225 wpc and damping factor of 80, the Anthem is a great match as an integrated amp.

[SteveB]

OK. This complicates things a bit and may change budgetary considerations. What are your long-range plans? Do you already have an HDTV? How many HDMI inputs does it have? If you're planning to get an HDTV, most of them now can switch among 4 HDMI inputs.

Right now I run an old rear projection HDTV with DVI and component inputs, no HDMI. At some point I'll upgrade the TV and it seems that more devices are using HDMI as standard connections these days, including audio ones. Still, I don't really care that much about Surround, so it might make sense to go with a two channel preamp and let the TV eventually take care of HDMI switching as needed.

[SteveB]

Actually what looks interesting is something like the Marantz SR5005 receiver. It has a full set of preamp outs to use with whatever external poweramp I decide on. I could run the main LR to a poweramp to the 8.1s, and then use the recievers own amp to power my surround speakers which I do have but currently arn't being driven. I could probably even send the center channel to the TV itself. The SR5005 is 3D HDMI capable to so it's up to full specs. And it's got a street price of around $500, which is decent.

[JohnnyB]

Actually what looks interesting is something like the Marantz SR5005 receiver. It has a full set of preamp outs to use with whatever external poweramp I decide on. I could run the main LR to a poweramp to the 8.1s, and then use the recievers own amp to power my surround speakers which I do have but currently arn't being driven. I could probably even send the center channel to the TV itself. The SR5005 is 3D HDMI capable to so it's up to full specs. And it's got a street price of around $500, which is decent.

That might be a better solution in your case. If you have a center channel speaker, you may want to consider this power amp. Price is right, very high current, and gives you a power match for left, center, and right speakers.

Trust me, your Kappas will be much happier with 200-300 watts each than 40-80.

[SteveB]

That might be a better solution in your case. If you have a center channel speaker, you may want to consider this power amp. Price is right, very high current, and gives you a power match for left, center, and right speakers.

Trust me, your Kappas will be much happier with 200-300 watts each than 40-80.

cool, thanks. What spec actually tells you if an amp is high current?

[JohnnyB]

What spec actually tells you if an amp is high current?

The primary spec would be peak current expressed in amperes, but many makers don't give that spec. There are other indicators of high current design. One hint is what the rated FTC power is into 4 ohms, and if the amp has an FTC 2-ohm power rating, it's almost certainly high current.

For example, if an amp is rated at 100 wpc into 8 ohms, if it is very high current it'll put out 200 wpc into 4 ohms and 400 wpc into 2 ohms. There aren't too many of those and they're usually very expensive. In affordable amps, an amp that's 200 wpc into 8 ohms and 350 wpc into 4 ohms should do the trick.

Other indicators of high current include the size of the transformer and filter capacitors and the overall weight of the amp relative to its rated power (unless it's a class D or T switching amp).

One that confuses me a bit is that Creek Evolution 2. One the one hand it's rated at 80 wpc into 8 ohms and 145 wpc into 4 ohms, and that's very good. OTOH, it only weighs 19 lbs, which is pretty light for an amp rated at 145 wpc into 4 ohms, so I'm not sure. Still, 10 amps isn't particularly high current and I think your Kappas would rather have 150 watts behind them than 80. This Denon integrated amp is rated at 80 wpc into 8 ohms, 160 wpc into 4 ohms, and weighs 57 lbs. That's a high current design.

I have a 150 wpc amp that weighs about 45 lbs. It's not only rated 300 wpc into 4 ohms, it's even stable into 0 ohms (a short circuit). That's high current too.

The amps I recommended from Emotiva, Parasound, and Outlaw weigh around 40-45 lbs. for 2 channels of power at 150 wpc or more and have a fairly impressive power increase into 4-ohm power ratings.

[SteveB]

I have a 150 wpc amp that weighs about 45 lbs. It's not only rated 300 wpc into 4 ohms, it's even stable into 0 ohms (a short circuit). That's high current too.

sounds like it could double as a welder.

[JohnnyB]

I have a 150 wpc amp that weighs about 45 lbs. It's not only rated 300 wpc into 4 ohms, it's even stable into 0 ohms (a short circuit). That's high current too.

sounds like it could double as a welder.

Some amps designed for ultimate stability can function as welders. I read a '70s test report of the Crown DC300A where the reviewer attached screwdrivers to the speaker leads and welded them together. If you Google Crown DC300A welding you'll get some hits on this ability. Also, instead of a lower bandwidth limit of 20 Hz, the Crown's bottom frequency response was specified as DC (or 0 Hz).

[SteveB]

Some amps designed for ultimate stability can function as welders. I read a '70s test report of the Crown DC300A where the reviewer attached screwdrivers to the speaker leads and welded them together. If you Google Crown DC300A welding you'll get some hits on this ability. Also, instead of a lower bandwidth limit of 20 Hz, the Crown's bottom frequency response was specified as DC (or 0 Hz).

I found the instruction manual online... that thing is a beast.

[JohnnyB]

Have you found an amp yet? Any candidates? Budget?

[gregc]

Look for a used McCormack! DNA 100, or better...

[JGale]

http://www.soundsgoodtomehouston.com/invsep.htm

has some stuff.

[SteveB]

at the moment I'm actually powering them with my QSC power amp. It's actually working pretty well, but I'll replace it with something else at some point.

[SteveB]

http://www.soundsgoodtomehouston.com/invsep.htm

has some stuff.

I need to wander over there and check that stuff out some time.

[JohnnyB]

http://www.soundsgoodtomehouston.com/invsep.htm has some stuff.

I need to wander over there and check that stuff out some time.

Especially check out the B&K ST-3030 and the Perreaux.

[SteveB]

Hey guys.... anybody know anything about the Sherwood S7000 or JVC JA-S22? A friend has these units gathering dust in his house.

[JohnnyB]

Hey guys.... anybody know anything about the Sherwood S7000 or JVC JA-S22? A friend has these units gathering dust in his house.

If you're looking for some nice vintage medium-powered receivers, they're both nice. The Sherwood is about 35 wpc tube receiver w/7591 output tubes. The Sherwood in good condition can fetch as much as $450.

But if you're still looking for high current high damping factor power for your Infinity's, these ain't it.

[SteveB]

But if you're still looking for high current high damping factor power for your Infinity's, these ain't it.

Yeah I figured the JVC wasn't but wasn't sure about the tube powered Sherwood. It's kinda cool though. Thanks.

[JohnnyB]

But if you're still looking for high current high damping factor power for your Infinity's, these ain't it.

Yeah I figured the JVC wasn't but wasn't sure about the tube powered Sherwood. It's kinda cool though. Thanks.

Your Infinity's were made at the height of solid state popularity. They have fairly large woofers and pretty much demand not only high current but a high damping factor to control the woofer. Tube electronics (especially a mid-fi receiver like the Sherwood) have a high output impedance and therefore a low damping factor, which is why most tube-driven bass is looser than what solid state serves up.

I have one of these, and they are fabulous. It should be an excellent match for your speakers and these amps are way better than the prices they fetch. My Heathkit AA-1600 anchors my 2-channel LP-based system. Hey--I just noticed that the vendor is our own Alpep. Maybe you could negotiate the shipping cost a bit.

[gorch]

Lookout for a Myryad MI 120. They are Hi-end for low money. Try to find one with the phono module if you still have records.

http://www.hometheaterhifi.com/volume_4_3/myryadmi120.html

I run one of those with a pair of refurbished Ohm L. Very transparent sound with natural depth.

[LostArt]

But if you're still looking for high current high damping factor power for your Infinity's, these ain't it.

Yeah I figured the JVC wasn't but wasn't sure about the tube powered Sherwood. It's kinda cool though. Thanks.

Your Infinity's were made at the height of solid state popularity. They have fairly large woofers and pretty much demand not only high current but a high damping factor to control the woofer. Tube electronics (especially a mid-fi receiver like the Sherwood) have a high output impedance and therefore a low damping factor, which is why most tube-driven bass is looser than what solid state serves up.

I have one of these, and they are fabulous. It should be an excellent match for your speakers and these amps are way better than the prices they fetch. My Heathkit AA-1600 anchors my 2-channel LP-based system. Hey--I just noticed that the vendor is our own Alpep. Maybe you could negotiate the shipping cost a bit.

that is one great sounding amp and one heavy mofo

if interested let me know